Clonal heterogeneity in chronic lymphocytic leukemia cells: superior response to surface IgM cross-linking in CD38, ZAP-70-positive cells.

Background Patients with chronic lymphocytic leukemia whose cells express CD38 and ZAP-70 and utilize unmutated Ig VH region genes have a very poor prognosis. We studied whether cells expressing CD38 and ZAP-70 are more susceptible to stimulation through B-cell receptors than are cells that do not express CD38 and ZAP-70.Design and Methods CD38-positive and CD38-negative leukemic cells were separated from single cases and compared for their response to B-cell receptor cross-linking and ZAP-70 expression. Cohort studies were also carried out by measuring the apoptotic response to surface immunoglobulin M (IgM) cross-linking in 82 patients with chronic lymphocytic leukemia and the protein tyrosine phosphorylation induced by surface IgM in 21 patients.Results CD38-positive cells, isolated from cases of chronic lymphocytic leukemia classified as CD38-positive or CD38-negative, expressed more ZAP-70 than the corresponding CD38-negative cells, exhibited more robust protein tyrosine phosphorylation and had a greater tendency to apoptosis upon B-cell receptor cross-linking. In the cohort studies, surface IgM-induced protein tyrosine phosphorylation correlated significantly with CD38 and ZAP-70 expression and with the absence of Ig VH gene mutations. Apoptosis induced by surface IgM cross-linking correlated significantly only with the proportion of CD38-positive cells. Difficulties in finding more definitive correlations were probably related to imprecision in the in vitro test system and in the definition of cases as positive or negative.Conclusions Collectively, these data indicate that CD38-positive, ZAP-70-positive cells have a greater capacity for signaling through the B-cell receptor and suggest a function for B-cell receptor signaling in promoting chronic lymphocytic leukemia cell expansion, especially within the CD38-positive fraction of the leukemic clone

Prognostic or predictive value of circulating cytokines and angiogenic factors for initial treatment of multiple myeloma in the GIMEMA MM0305 randomized controlled trial

Abstract Background Several new drugs are approved for treatment of patients with multiple myeloma (MM), but no validated biomarkers are available for the prediction of a clinical outcome. We aimed to establish whether pretreatment blood and bone marrow plasma concentrations of major cytokines and angiogenic factors (CAFs) of patients from a phase 3 trial of a MM treatment could have a prognostic and predictive value in terms of response to therapy and progression-free and overall survival and whether these patients could be stratified for their prognosis. Methods Blood and bone marrow plasma levels of Ang-2, FGF-2, HGF, VEGF, PDGF-β, IL-8, TNF-α, TIMP-1, and TIMP-2 were determined at diagnosis in MM patients enrolled in the GIMEMA MM0305 randomized controlled trial by an enzyme-linked immunosorbent assay (ELISA). These levels were correlated both reciprocally and with the type of therapy and patients’ characteristics and with a group of non-MM patients as controls. Results No significant differences were detected between the blood and bone marrow plasma levels of angiogenic cytokines. A cutoff for each CAF was established. The therapeutic response of patients with blood plasma levels of CAFs lower than the cutoff was better than the response of those with higher levels in terms of percentage of responding patients and quality of response. Conclusion FGF-2, HGF, VEGF, and PDGF-β plasma levels at diagnosis have predictive significance for response to treatment. The stratification of patients based on the levels of CAFs at diagnosis and their variations after therapy is useful to characterize different risk groups concerning outcome and response to therapy. Trial registration Clinical trial information can be found at the following link: NCT0106317

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Measurement of isolated-photon plus jet production in pp collisions at √s=13 TeV with the ATLAS detector at the LHC

Dottorato di Ricerca in Scienze e Tecnologie Fisiche, Chimiche e dei Materiali. Ciclo XXXThe study of the production of prompt photons in association with hadronic jets provides a test of perturbative Quantum Chromodynamics and gives information on the proton parton distribution functions. The colorless prompt photon represents a clean probe of the hard partonic interaction since the photon is produced in the hard scattering and does not undergo hadronization. The measurement of the angular correlations between the photon and the hadronic jets is a test of perturbative Quantum Chromodynamics at large hard scattering scales and over a large range of proton momentum fraction. In this thesis, the dynamics of isolated-photon production in association with a jet in proton-proton collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the Large Hadron Collider using a dataset with an integrated luminosity of 3.2 fb−1. Photons are required to have transverse energies above 125 GeV. Jets are identified using the anti-kt algorithm with radius parameter R = 0.4 and are required to have transverse momenta above 100 GeV. Measurements of isolated-photon plus jet cross sections are presented as functions of the leading-photon transverse energy, the leading-jet transverse momentum, the azimuthal angular separation between the photon and the jet, the photon-jet invariant mass and the scattering angle in the photon-jet centre-of-mass system. Tree-level plus parton-shower predictions from Sherpa and Pythia as well as next-to-leading-order QCD predictions from Jetphox and Sherpa are compared to the measurements.Università della Calabri